Vacuum tube



Jan. 24, 1928..

V. F. GREAVES VACUUM TUBE Filed March 23. 1925 In v'entor. V $7 $7 6M.

(HZ/$01 ys.

Patented Jan. 24, 1928.

{UNITED STATES PATENT oFiucEJ' VALENTINE FORD GREAVES, OF OAKLAND, CALIFORNIA, ASSIGNOR TO THE MAGNA- VOX COMPANY, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF ARIZONA.

VACUUM TUBE.

Application filed-March 23, 1925. Serial No. 17,508.

This invention relates to vacuum tubes, particularly oi the three electrode type for use as rectifiers, amplifiers and electric wave generators. The object of the invention is to perfect the construction of the ends of the wires leading to the various elements of such a device, whereby poor contacts are entirely eliminated, and whereby the contact between the wires leading from the elements and the prongs in the base, is made perfect Without the use of solder or other oxidizable material.

It is well known that a contact between solder and other metals such as is usually employedin the sockets of receiving sets which is maintained by pressure only, is not satisfactory or dependable from the electrical point of view, because of the heavy coat of insulating oxide which rapidly formson lead, solder, etc.

In case of difficulty or trouble with radio receivers using vacuum tubes, it has been customary in an eifort to locate the difiiculty, to remove the tube and clean the solder contacts. It is safe to say that most of the diflicult with inoperative or defective vacuum tu e receivers, has been due to poor contacts between solder base prongs and spring sockets.

In the present invention I make a cold weld between the lead wires and the base prongs, therebv entirely eliminating any solder and at the same time make the contact between the wire and the prong even more effective than soldering or riveting.

In the accompan ing drawing I have illustrated one speci c embodiment of my invention, but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as definin or limiting the S00 e of the invention, the c aims appended to t e specification bein relied upon for that purpose.

' Iteferring to the figures of the drawing Fig. 1 is a perspective view of a vacuum tube constructed in accordance with my invention.

Figs. 2, 3 and 4 are enlarged sectional views showing the. three steps of operation in my improved process.

Fig. 5 1s a bottom plan view of the prong contact shown in 'Fi 4.

Inthe drawing, dicates the bulb, 2

the base and 3 the contact prongs of a radio vacuum tube. These prongs are secured to the base in the manner shown in Figs. 2, 3 and 4. Each prong is provided with a hole 4 centrally therethrough for receiving a lead-in wire 5 as hereinafter described.

In my improved process, the wires are first threaded through the holes 4 of the prongs in the manner illustrated in Fig. 2..

The outer end portions 6 of the prongs are then upset in a power press to crush the same into firm contact with the wires as illustrated in Fig. 3. The end portion 7 of the wire is then severed and the end of the prong and wire is finished off to form a smooth contact as illustrated in Figs. 4. and 5.

It is believed that the advantages of-my improvement will be obvious without further description. The upsetting pressure on the prongs is so great that in etfect a cold weld is formed between the prong and wire. Furthermore, the Wire extends entirely to the end of the prong whereby contact is formed directly with the end of the wire at 8, thus an excellent contact is assured under practically all conditions and over long periods of time without the necessity of cleaning. Also in addition to eliminating all solder and making a better contact, manufacturing costs with this process are reduced toa very great extent.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. The process of forming improved contacts for radio vacuum tubes which consists of threading each lead-in wire through a hole in a base prong, severing the wire at the end of the pron and forming a joint therebetween by crus ing the outer end portion of each Erong into close contact with its wire, and nishing off the outer ends of the prongs and wires to form a smooth contact. A

2. In a vacuum tube, the combination of a base, a plurality of tubular prongs there on formin sockets, an wires leading to the electrodes, each wire extending through a tubular prong, and said prong being crushed into thewire in a manner to form a tight joint.

VALENTINE FORD GREAVES.

terminals for connectlon with 

